Safety-shutter for cinematograph-projectors



A. H. WILLMANN.

SAFETY SHUTTER FOR CINEMATOGRAPH PROJECTORS.

APPLICATION FILED AUG-25, 1919.

Patented Dec. 7, 1920.

2 SHEETS-SHEET I- Fly! Fig.2.

A. H. WILLMANN.

SAFETY SHUTTER FOR CINEMATOGRAP H PROJECTORS. APPLICATION FILED AUG-25.1919.

1,3 1,430, 4 Patented Dec. 7,1920.

2 SHEETS-SHEET 2.

WL'massas. JTLI/E/ZZOF & M. W w M M ALFRED HENRY WILLMANN,

PATENT OFFICE.

01? WIMBLEDON, ENGLAND.

SAFETY-SHUTTER FOR CINEMATOGRAPH-PROJECTORS.

Application filed August 25 Tea whom it may 50mm:

-- Be it known that I, ALFRED HENRY WViLL- MANN, a subject of the Kingof Great Britain, residing at 13 Mina Road, Merton Park, Wimbledon,Surrey England, have invented new and useful Improvements in SafetyShutters for Cinematograph-Proj ectors, of which the follopving is aspecifica; I tion. a My invention relates to safetyshutters foraifording protection against fire in ciriematograph projectors, and tothat class of such shutter having combined with it means whereby it isretained in the open position so long as the film is intactbut closes ifthe film breaks. In apparatus of this class as heretofore constructedthe releasing device for the safety shutter is placed in such apositionwith relation to'thegate or trap through which the film passesthat it is necessaryto draw the film out of the tfiaploefore the deviceoperates. To overcome t is objection it has been proposed to provide aduplicate shutter to operate in case the film breaks before it enterstlie gate.

According to my invention I arrange the releasing device to bear againstthe film close to the\point at which it issues from the gate .so thatthe safety shutter will operate almost instantaneously in case the filmbreaks in the gate.

In carrying out my invention I employa pendulous arm or lever whichpresses upon the film as it issues from the said gate and I combine withthis lever a second lever carrying a catch which engages with theshutter-to retain it open so loilg as the film is intact, but whichshould the film break and allow the pendulous lever to move relativelythereto will release the said catch and allow the shutter toclose.

My invention will be readily understood byreference. to the accompanyingdrawing, in which: I

Figure l is an elevation illustrating an arrangement wherein a; singleshutter is emplb ed, and

igs. 2.. and 3 are sections onthehnes- 2-2, and 3 3, respectively ofFig. 1.

Fig. 4 is an elevation illustrating a modification of. my invention, and

Fig. 5 is a section on the line 5- 5,

Fig. 6 is a planof the same. I In the arrangement of -my inventionSpecification of Iietters Patent. i

1919. Serial No. 319,570.

shown in Figs. 1 to 3 (1 indicates th front plate and b the gate whichis combined therewith and which, as shown, is designed to slide backwardupon the rods 6 b to allow the film 0 to be inserted between the saidgate and said front plate. 0 c are gate respectively, through which thelight is projected. .d is the safety shutterwhich,

as shown, is mounted on a pivot d and which is cut away or shaped as ate to expose the aperture 0 Patented Dec. '7, 1920.

theapertures formed in the front plate and latter to uncover theaperture 0 as shown in r the drawing, and in combination with the saidcatch lever I provide a pendulous arm .9 pivoted-upon the plate a andthe free inturned end 9 of which is-designed to bear against the film 0.

In practice the catch lever f is formed with two arms, one of whichcarries a sprlng pawl it which constitutes the catch proper and engageswith the tooth f and the other of which at the endiz. cooperates with anincline or curved surface a on the pendulous arm in such a manner that aspring 2' which 1 pulls upon the said leyer f serves to press the end ofthe pendulous arm against the 3 film c, as clearly shown in Fig. 2.

1c is an electric switch fixed upon the front plate a and which, asshown, is provided with four terminals, two of which are in the circuitof the operating motor'and the other two in a bell or other alarmcircuit. The contact bar or lever Z of this switch is designed to beactuated by the shutter at when the latter is moved; as shown, the saidshutter is provided with two arms m,.m the arm m serving, when theshutter is moved to uncover the aperture 0 to strike the contact bar 1and switch on the motor current, while the otherarm m -is designed, inthe case of a film breaking-and releasing the shutter, to strike thecontact bar and switch off the currentfrom the motor and close the swinginward under the action of the spring i acting on the lever f andrelease the shutter which will close the aperture 0.

In practice I find it advantageous to provide for adjusting the pawl hwith relation to the tooth f according to the thickness of filmemployed, that is to say, I arrange that it does not gear so deeply forthick films as for thin films owing to the former not yielding so easilywhen broken. For this purpose arrange the pivot oi the lever i so thatit can be moved longitudinally, this being advantageously efi'ected by af as shown c rly in Fig. 3.

In cases w ere the sprocket wheel causes the trawl of the film is arrane so close t aperture 0 that sufiicient space is not ed for applying thependulons lever J' between the aperture and the said sprocket wheel, Iadvantageously make use of ngcinent illustrated in 4.-

In this modification n is the pen arm which is arranged below thesprocket wheel n which point the tensionfon the film is not snfiicientto retain the pendulons arm in the equired position to lock the shut teropen. I therefore provide in coniunction with the said pendulous arm a pr of rollers 0, 0 or other support, over w he film will run and betweenwhich the r of the p idinous arm will pass, in s manner, rat so long asthe film is int W the pendulons arm will remain in the p sition shown inFig. 5, but so that when the broken end of the and the catchlever rengages with only one of the said sections as shownin Fig. 4. lhis catchlever r operates in conjunction with the lever n in the same way asdescribed with reference to Fig. 1.

The switch which controls the operating motor and is shown in Figs. 4and 6, has its controlling arm 8 connected on one side of its pivot withone section of the shutter, say, by a chain i or'other flexibleconnection, in such a manner that the opening of the shutter will serveto operate the switch to start the motor. dhe other end of the saidoperating lever is connected by a chain or the like to a trip lever Mwhich will be including a. nli :1

film comes opposite to the gap" between the said rollersthe penduiousarm struck by one leaf of the shutter, when the latter drops, to openthe switch to stop the motor. r

'In the switch shown in the drawing the contact arm 2; is pressed towardthe operating arm by a spring 10 and a notch so is formed therein. henthe shutter is open the arm 8 holds down the contact arm 11 as shown inFig. 6. hen, however, the shutter isreleased and the trip lever'u isoperated as above described the arm 8 is moved to the position indicatedby the dotted lines in i in which it is opposite to the notch m, thesaid contact arm being thereby free to rise under the action oi thespring 10 to open the switch to stop the motor.

Claims.

A. cinematograph projecting appa 'atus guid having an aperture for the pjQCfiiOH of the light and film driving or supporting roller adjacent tothe said guide, a pivotally mounted shutter movable in a plane parallelto that of the guide passage and designed to close said aperture, arocking lever having one of its ends engaging the shutter for holdingthe same in open position, a pendulous lever bear ing upon one face ofthe film and engaging 'he other end of the rocking lever for holding thelatter in looking position, and means operating upon breaking of the tocause the rocking lever to release the shutter to permit the same toclose.

2. An apparatus of the kind defined in shutter movable in a planeparallel to the I face of said plate and designed to close saidapertures, a. rocking lever having one of its ends engaging the shutterfor holding the same in open position, a pendulous lever bearingup'onone face of the film and engaging the other end of the rocking lever forholding the'latter in looking position, and means operating uponbreaking of the film to cause the rocking lever to release the shutterto permit the same to close.

- 4:. An apparatus of the kinddefined in claim 5, in which rollersbetween which the film passes, are arranged adjacent'the point at whichthe film issues fromthe film guide,

and the part of the pendulous lever which engages the film being movablebetween the rollers when the film breaks.

ALFRED HENRY wiLLMAnn.

including a plate and a film guide having registering apertures, apivotally mounted

